The present invention addresses a liquid-filled thermostatic system for controlling heat valves. The system comprises an activating device which is provided with a pressure control and serves to select a desired temperature and acts as a sensor. The system further comprises an operating device which is detachably mounted onto a valve housing and acts on the heat valve. The activating device is connected to the operating device by means of a capillary tube. The activating device is provided with an adjusting knob, a housing comprising a preferably pot-shaped cover and a bottom, a bellows-type tube coaxially disposed inside the housing and a mounting device for mounting the housing to a wall or the like, said mounting device preferably extending circularly around the housing. Together, the housing and the bellows-type tube form a liquid-containing space of a variable volume. The bellows-type tube has a bottom which can be axially adjusted by means of the adjusting knob and an adjusting device.
Liquid-filled thermostatic systems of the kind in question are already known (DE-PS 21 65 231). In these known systems, the activating device is configured such that at its end facing the adjusting knob, the bellows-type tube which is coaxially disposed inside the housing is via a bearing plate mounted to the adjusting knob. The free end of the bellows-type tube extends in direction of the rear plate of the housing, said rear plate acting as a pressure control. This free end extends considerably into an area of the housing which is surrounded by a mounting device by which it is also more or less insulated from the outside.
Accordingly, at least the front part of the sensor of the known activating device comprising the bellows-type tube and the housing is, on the one hand, affected by radiation from the wall and, on the other, insufficiently ventilated at the walls of the housing. In the known system, it is, hence, not possible to exactly detect room temperatures. On the contrary, the activating device is subject to numerous considerable interferences. Satisfactory temperature control is hence not guaranteed.
It is therefore an object of the invention to provide a liquid-filled thermostatic system for controlling heat valves where the activating device is allowed to react to changes in the room temperature while being largely free from interference and where the control variable derived from the room temperature is fed by said acivating device via the capillary tube to the operating device mounted to the valve housing.